U.S. patent number 8,280,259 [Application Number 12/618,613] was granted by the patent office on 2012-10-02 for radio-over-fiber (rof) system for protocol-independent wired and/or wireless communication.
This patent grant is currently assigned to Corning Cable Systems LLC. Invention is credited to Jacob George, Michael Sauer, Dean M. Thelen.
United States Patent |
8,280,259 |
George , et al. |
October 2, 2012 |
Radio-over-fiber (RoF) system for protocol-independent wired and/or
wireless communication
Abstract
An optically-switched fiber optic communication system, such as
a Radio-over-Fiber (RoF) based optical fiber link system, may be
used to increase the range of peer-to-peer communications. The
optically-switched fiber optic communication system may include a
head-end unit (HEU) having an optical switch bank. Fiber optic
cables comprising optical fibers optically couple the HEU to one or
more remote access points in different coverage areas. The optical
switch bank in the HEU provides a link between the remote access
points in the different coverage areas such that devices in the
different cellular coverage areas can communicate with each other
over the optical fibers through the HEU. By using the
optically-switched fiber optic communication system, the range and
coverage of communication between devices may be extended such that
devices in different coverage areas and devices using different
communication protocols can communicate.
Inventors: |
George; Jacob (Horseheads,
NY), Sauer; Michael (Corning, NY), Thelen; Dean M.
(Addison, NY) |
Assignee: |
Corning Cable Systems LLC
(Hickory, NC)
|
Family
ID: |
43568338 |
Appl.
No.: |
12/618,613 |
Filed: |
November 13, 2009 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20110116794 A1 |
May 19, 2011 |
|
Current U.S.
Class: |
398/115; 370/503;
370/466; 370/389; 398/116; 370/338; 370/392; 398/50; 398/48;
398/45; 398/58; 398/128; 398/49; 398/118; 370/342; 398/130;
398/117; 370/328; 370/351; 370/352; 455/562.1; 455/561 |
Current CPC
Class: |
H04W
16/26 (20130101); H04B 10/25751 (20130101); H04Q
11/0067 (20130101); H04N 7/15 (20130101); H04W
88/085 (20130101); H04B 10/25754 (20130101); H04W
84/12 (20130101); H04W 88/08 (20130101); H04W
76/10 (20180201); H04W 92/20 (20130101) |
Current International
Class: |
H04B
10/00 (20060101) |
Field of
Search: |
;398/115,45,48,46,49,79,66,70,72,68,98,99,100,57,58,116,117,118,71,128,130,126
;455/561,562.1,562,445,422,524,560,403
;370/338,392,342,329,315,328,318,351,352,465,466,503,474 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Phan; Hanh
Attorney, Agent or Firm: Montgomery; C. Keith
Claims
What is claimed is:
1. An optical fiber-based wireless communication system,
comprising: a head-end unit (HEU) having an optical switch bank;
and a plurality of fiber optic cables each comprising at least one
optical fiber and configured to carry a Radio-over-Fiber (RoF)
signal from the HEU to a plurality of remote access points, wherein
a first one of the plurality of remote access points is configured
to form a corresponding first coverage area, and a second one of
the plurality of remote access points is configured to form a
corresponding second, different coverage area, wherein the optical
switch bank is configured to dynamically establish a RoF-based
optical link over at least one of the plurality of fiber optic
cables such that a first peer device in the first coverage area can
communicate with a second peer device in the second coverage area
at least in part over the RoF-based optical link, and wherein the
HEU is further configured to receive a request from a first one of
the first and second peer devices to communicate with a second one
of the first and second peer devices via at least one Wireless
Local Area Network (WLAN) access point associated with at least one
of the first and second peer devices.
2. The optical fiber-based wireless communication system of claim
1, wherein the first one of the plurality of remote access points
is configured to wirelessly communicate with the first peer device;
and the second one of the plurality of remote access points is
configured to wirelessly communicate with the second peer
device.
3. The optical fiber-based wireless communication system of claim
1, wherein the first and second ones of the plurality of remote
access points are broadband access points.
4. The optical fiber-based wireless communication system of claim
1, wherein the HEU is further configured to automatically establish
the RoF-based optical link between the first coverage area and the
second coverage area when signals received at the HEU from the
first peer device in the first coverage area and signals received
from the second peer device in the second coverage area have common
radio frequencies.
5. The optical fiber-based wireless communication system of claim
1, wherein the HEU is optically coupled to the at least one WLAN
access point via a fiber optic cable comprising at least one
optical fiber.
6. The optical fiber-based wireless communication system of claim
1, wherein the first one of the plurality of remote access points
is configured to wirelessly communicate with the first peer device
using a different wireless communication protocol than a protocol
used by the second one of the plurality of remote access points to
wirelessly communicate with the second peer device.
7. The optical fiber-based wireless communication system of claim
6, wherein at least one of the wireless communication protocols
used by the first one or second one of the plurality of remote
access points to wirelessly communicate with the first or second
peer device is a proprietary wireless communication protocol.
8. The optical fiber-based wireless communication system of claim
1, wherein the optical switch bank further comprises at least one
optical amplifier.
9. The optical fiber-based wireless communication system of claim
1, wherein the HEU further comprises a video broadcast unit
configured to split a video signal received at the HEU to a
plurality of devices over a plurality of fiber optic cables
comprising at least one optical fiber.
10. The optical fiber-based wireless communication system of claim
1, wherein at least one of the plurality of remote access units
further comprises at least one of a radio frequency (RF)
input/output, a DC input/output, and an optical input/output.
11. The optical fiber-based wireless communication system of claim
10, wherein at least one of the plurality of remote access units
further comprises at least one of a laser diode, a photo detector,
a transimpedance amplifier, and at least one switch configured to
selectively connect at least one optical fiber to either the RF
input/output and/or the optical input/output.
12. The optical fiber-based wireless communication system of claim
1, further comprising a processor in the HEU configured to process
requests for peer-to-peer communication between the first and
second peer devices.
13. The optical fiber-based wireless communication system of claim
1, wherein the RoF-based optical link is all optical.
14. An optical fiber-based wireless communication system,
comprising: a head-end unit (HEU) having an optical switch bank;
and a plurality of fiber optic cables each comprising at least one
optical fiber and configured to carry a Radio-over-Fiber (RoF)
signal from the HEU to a plurality of remote access points, wherein
a first one of the plurality of remote access points is configured
to form a corresponding first coverage area, and a second one of
the plurality of remote access points is configured to form a
corresponding second, different coverage area, wherein the optical
switch bank is configured to dynamically establish a RoF-based
optical link over at least one of the plurality of fiber optic
cables such that a first peer device in the first coverage area can
communicate with a second peer device in the second coverage area
at least in part over the RoF-based optical link, and wherein at
least one of the first and second ones of the plurality of remote
access points is a coexistent access point configured to
communicate via both Wireless Local Area Network (WLAN) and
broadband signals.
15. The optical fiber-based wireless communication system of claim
14, wherein the at least one coexistent access point is optically
coupled to the HEU via a fiber optic cable comprising at least one
optical fiber.
16. The optical fiber-based wireless communication system of claim
14, wherein the RoF-based optical link is all optical.
17. The optical fiber-based wireless communication system of claim
14, wherein at least one of the plurality of remote access units
further comprises at least one of a radio frequency (RF)
input/output, a DC input/output, and an optical input/output.
18. An optical fiber-based wireless communication system,
comprising: a head-end unit (HEU) having an optical switch bank;
and a plurality of fiber optic cables each comprising at least one
optical fiber and configured to carry a Radio-over-Fiber (RoF)
signal from the HEU to a plurality of remote access points, wherein
a first one of the plurality of remote access points is configured
to form a corresponding first coverage area, and a second one of
the plurality of remote access points is configured to form a
corresponding second, different coverage area, wherein the optical
switch bank is configured to dynamically establish a RoF-based
optical link over at least one of the plurality of fiber optic
cables such that a first peer device in the first coverage area can
communicate with a second peer device in the second coverage area
at least in part over the RoF-based optical link, further
comprising at least one Wireless Local Area Network (WLAN) access
point configured to receive a request from a device other than the
first and second peer devices to establish communications between
the first and second peer devices.
19. The optical fiber-based wireless communication system of claim
18, wherein the RoF-based optical link is all optical.
20. The optical fiber-based wireless communication system of claim
18, wherein at least one of the plurality of remote access units
further comprises at least one of a radio frequency (RF)
input/output, a DC input/output, and an optical input/output.
21. A method of enabling communication between a first peer device
in a first coverage area and a second peer device in a second,
different coverage area, comprising: optically linking a plurality
of remote access points to a head-end unit (HEU) via a plurality of
fiber optic cables, each of the plurality of fiber optic cables
comprising at least one optical fiber and configured to carry a
Radio-over-Fiber (RoF) signal from the HEU to the plurality of
remote access points; forming a first coverage area associated with
a first one of the plurality of remote access points; forming a
second coverage area associated with a second one of the plurality
of remote access points different from the first coverage area;
dynamically establishing a RoF-based optical link over at least one
of the plurality of fiber optic cables to allow the first peer
device to communicate with the second peer device at least in part
over the RoF-based optical link; and receiving a request to
establish communications between the first peer device and the
second peer device from a device other than one of the first and
second peer devices.
22. The method of claim 21, further comprising the first one of the
plurality of remote access points wirelessly communicating with the
first peer device and the second one of the plurality of remote
access points wirelessly communicating with the second peer
device.
23. The method of claim 21, further comprising receiving a request
to establish communications between the first peer device and the
second peer device from one of the first and second peer
devices.
24. The method of claim 21, further comprising: sensing a radio
frequency of at least one signal received from the first peer
device in the first coverage area and a radio frequency of at least
one signal received from the second peer device in the second
coverage area; and automatically establishing the RoF-based optical
link between the first coverage area and the second coverage area
when the radio frequency of the at least one signal received from
the first peer device in the first coverage area and the radio
frequency of the at least one signal received from the second peer
device in the second coverage area are common radio
frequencies.
25. The method of claim 21, further comprising the first one of the
plurality of remote access points wirelessly communicating with the
first peer device using a different wireless communication protocol
than a protocol used by the second one of the plurality of remote
access points to wirelessly communicate with the second peer
device.
26. The method of claim 21, further comprising at least one of the
plurality of remote access points wirelessly communicating with at
least one of the first or second peer device using a proprietary
wireless communication protocol.
27. The method of claim 21, further comprising exchanging data
between the first and second peer devices at least in part over the
RoF-based optical link.
28. The method of claim 21, wherein the RoF-based optical link is
all optical.
29. A method of enabling communication between a first peer device
in a first coverage area and a second peer device in a second,
different coverage area, comprising: optically linking a plurality
of remote access points to a head-end unit (HEU) via a plurality of
fiber optic cables, each of the plurality of fiber optic cables
comprising at least one optical fiber and configured to carry a
Radio-over-Fiber (RoF) signal from the HEU to the plurality of
remote access points; forming a first coverage area associated with
a first one of the plurality of remote access points; forming a
second coverage area associated with a second one of the plurality
of remote access points different from the first coverage area;
dynamically establishing a RoF-based optical link over at least one
of the plurality of fiber optic cables to allow the first peer
device to communicate with the second peer device at least in part
over the RoF-based optical link; and receiving a request to
establish communications between the first peer device and the
second peer device at a Wireless Local Area Network (WLAN) access
point optically coupled to the HEU via a fiber optic cable
comprising at least one optical fiber.
30. The method of claim 29, wherein the RoF-based optical link is
all optical.
31. The method of claim 29, wherein at least one of the plurality
of remote access units further comprises at least one of a radio
frequency (RF) input/output, a DC input/output, and an optical
input/output.
Description
BACKGROUND
1. Field of the Disclosure
The technology of the disclosure relates to wired and/or wireless
communication systems employing a Radio-over-Fiber (RoF)
communication system.
2. Technical Background
Wireless communication is rapidly growing, with ever-increasing
demands for high-speed mobile data communication. As an example,
so-called "wireless fidelity" or "WiFi" systems and wireless local
area networks (WLANs) are being deployed in many different types of
areas (e.g., coffee shops, airports, libraries, etc.). Wireless
communication systems communicate with wireless devices called
"clients," which must reside within the wireless range or "cell
coverage area" in order to communicate with an access point
device.
One approach to deploying a wireless communication system involves
the use of "picocells." Picocells are radio-frequency (RF) coverage
areas. Picocells can have a radius in the range from a few meters
up to twenty meters as an example. Combining a number of access
point devices creates an array of picocells that cover an area
called a "picocellular coverage area." Because the picocell covers
a small area, there are typically only a few users (clients) per
picocell. This allows for simultaneous high coverage quality and
high data rates for the wireless system users, while minimizing the
amount of RF bandwidth shared among the wireless system users. One
advantage of picocells is the ability to wirelessly communicate
with remotely located communication devices within the picocellular
coverage area.
One type of wireless communication system for creating picocells is
called a "Radio-over-Fiber (RoF)" wireless system. A RoF wireless
system utilizes RF signals sent over optical fibers. Such systems
include a head-end station optically coupled to a plurality of
remote units. The remote units each include transponders that are
coupled to the head-end station via an optical fiber link. The
transponders in the remote units are transparent to the RF signals.
The remote units simply convert incoming optical signals from the
optical fiber link to electrical signals via optical-to-electrical
(O/E) converters, which are then passed to the transponders. The
transponders convert the electrical signals to electromagnetic
signals via antennas coupled to the transponders in the remote
units. The antennas also receive electromagnetic signals (i.e.,
electromagnetic radiation) from clients in the cell coverage area
and convert the electromagnetic signals to electrical signals
(i.e., electrical signals in wire). The remote units then convert
the electrical signals to optical signals via electrical-to-optical
(E/O) converters. The optical signals are then sent to the head-end
station via the optical fiber link.
Wired and wireless peer-to-peer analog and digital communications
are generally limited in range and coverage, respectively.
Enhancing the range of wired peer-to-peer connections may require
complicated amplifying and/or repeating requirements. Extending the
coverage of wireless peer-to-peer connections typically requires a
denser antenna deployment and/or transmitted power increase, which
may be limited by government regulations, wireless standards, and
battery peak power and energy storage considerations. In addition,
extending the coverage may be prohibited by the use of proprietary
protocols, such as medical equipment.
SUMMARY OF THE DETAILED DESCRIPTION
Embodiments disclosed in the detailed description include
optically-switched fiber optic wired and/or wireless communication
systems and related methods to increase the range of wired and/or
wireless peer-to-peer communication systems. In one embodiment, the
optically-switched fiber optic wired and/or wireless communication
system may include a head-end unit (HEU) having an optical switch
bank. A plurality of fiber optic cables, each of the plurality of
fiber optic cables comprising at least one optical fiber, are
configured to carry a Radio-over-Fiber (RoF) signal from the HEU to
a plurality of remote access points. A first one of the plurality
of remote access points is configured to form a corresponding first
cellular coverage area where a first peer device is located. A
second one of the plurality of remote access points is configured
to form a corresponding second, different cellular coverage area
where a second peer device is located. The optical switch bank is
configured to dynamically establish a RoF-based optical link over
at least one of the plurality of fiber optic cables such that the
first peer device communicates with the second peer device at least
in part over the RoF-based optical link.
Another embodiment disclosed herein provides a method of enabling
communication between a first peer device in a first cellular
coverage area and a second peer device in a second, different
cellular coverage area. The method may include optically linking a
plurality of remote access points to a HEU via a plurality of fiber
optic cables, each of the plurality of fiber optic cables
comprising at least one optical fiber and configured to carry a RoF
signal from the HEU to the plurality of remote access points. A
first one of the plurality of remote access points is configured to
form the first cellular coverage area. A second one of the
plurality of remote access points is configured to form the second,
different cellular coverage area. A request is received to
establish communications between the first peer device and the
second peer device, and in response to the request, dynamic
establishment of a RoF-based optical link is performed over at
least one of the plurality of fiber optic cables to allow the first
peer device to communicate with the second peer device at least in
part over the RoF-based optical link.
The systems and methods disclosed herein can be configured to
overcome the limitations of traditional wired and/or wireless
("wired/wireless") peer-to-peer communications by combining the low
loss, high bandwidth nature of optical fiber with an appropriate
optical switching network to enhance coverage (where needed). In
one embodiment, the optically-switched fiber optic wired/wireless
communication system is a RoF-based link system. In another
embodiment, the RoF-based link system is nearly protocol
transparent (i.e., independent of protocol).
The optically-switched fiber optic wired/wireless communication
systems and methods disclosed herein may include dense fiber cable
deployment (as in picocell), which facilitates cell-to-cell
peer-to-peer communication. By taking advantage of the fiber cable
architecture of the optically-switched fiber optic wired/wireless
communication system, such as a RoF Wireless Local Area Network
(WLAN) picocell system, the peer-to-peer communication range is
extended to be cell-to-cell. In this regard, devices in any two
cells can communicate in the peer-to-peer mode independent of their
physical distance, such that the peer-to-peer range extends across
entire indoor installation areas.
In addition, the optically-switched fiber optic wired/wireless
communication systems and methods disclosed herein can use optical
cable links that are nearly transparent to wireless protocols,
thereby eliminating proprietary protocol compliance requirements.
Thus, a broad variety of current applications/equipment are
supported without any infrastructure upgrade, including switched
video connection, switched video with Internet connection,
peer-to-peer proprietary protocol equipment (e.g. medical),
peer-to-peer videoconferencing, and broadcast capability (cellular
and video). In addition, future applications/equipment will be
possible without any infrastructure upgrade.
The optically-switched fiber optic wired/wireless communication
system and method disclosed herein take advantage of a local
wireless network, such as a WLAN, to initiate peer-to-peer
switching, because the switching only needs a very low data rate
connection. Multiple input options may be supported, such as a
radio frequency (RF) cable/antenna input, an optical fiber input,
and an electrical power input. Multiple output options can be used,
including an RF cable/antenna output, an optical fiber output with
optical/electrical conversion, an optical fiber output with the E/O
conversion bypassed, and an electrical power output. The
optically-switched fiber optic wired/wireless communication system
disclosed herein can be upgraded to higher frequencies, such as 60
Gigahertz (GHz).
Additional features and advantages will be set forth in the
detailed description which follows, and in part will be readily
apparent to those skilled in the art from that description or
recognized by practicing the embodiments as described herein,
including the detailed description that follows, the claims, as
well as the appended drawings.
It is to be understood that both the foregoing general description
and the following detailed description present embodiments, and are
intended to provide an overview or framework for understanding the
nature and character of the disclosure. The accompanying drawings
are included to provide a further understanding, and are
incorporated into and constitute a part of this specification. The
drawings illustrate various embodiments, and together with the
description serve to explain the principles and operation of the
concepts disclosed.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic diagram of an exemplary generalized
embodiment of an optical fiber-based wireless picocellular
system;
FIG. 2 is a schematic diagram of an exemplary Radio-over-Fiber
(RoF) distributed communication system;
FIG. 3 is a more detailed schematic diagram of an exemplary
embodiment of the system of FIG. 1, showing the head-end unit (HEU)
and one remote unit and picocell of the exemplary system of FIG.
1;
FIG. 4 is a schematic diagram of using an exemplary embodiment of
an optically-switched fiber optic wired and/or wireless
("wired/wireless") communication system to allow proprietary
protocol data transfer between peer-to-peer devices according to an
exemplary embodiment;
FIG. 5 is a schematic diagram of using an exemplary embodiment of
an optically-switched fiber optic wired/wireless communication
system to allow videoconferencing between peer-to-peer devices
according to an exemplary embodiment;
FIG. 6 is a schematic diagram of using an exemplary embodiment of
an optically-switched fiber optic wired/wireless communication
system to allow communication between peer-to-peer devices through
co-existent access points according to an exemplary embodiment;
FIG. 7 is a schematic diagram of an exemplary embodiment of an
optical switching bank at a HEU of an optically-switched fiber
optic wired/wireless communication system;
FIG. 8 is a schematic diagram of an exemplary embodiment of using
optical amplification and splitting at a HEU of an
optically-switched fiber optic wired/wireless communication system
for broadcasting video to peer-to-peer devices;
FIG. 9 is a schematic diagram of an exemplary embodiment of an
optically-switched fiber optic wired/wireless communication system
that illustrates an exemplary connection between a HEU and
broadband transponders in two different locations;
FIG. 10 is a schematic diagram of an exemplary embodiment of a
broadband transponder that may be used in an exemplary embodiment
of an optically-switched fiber optic wired/wireless communication
system;
FIG. 11 is a schematic diagram of an exemplary embodiment of a HEU
of an optically-switched fiber optic wired/wireless communication
system; and
FIG. 12 is a schematic diagram of an exemplary embodiment of a
Radio-over-Fiber based wireless communication system.
DETAILED DESCRIPTION
Reference will now be made in detail to the embodiments, examples
of which are illustrated in the accompanying drawings, in which
some, but not all embodiments are shown. Indeed, the concepts may
be embodied in many different forms and should not be construed as
limiting herein; rather, these embodiments are provided so that
this disclosure will satisfy applicable legal requirements.
Whenever possible, like reference numbers will be used to refer to
like components or parts.
Embodiments disclosed in the detailed description include
optically-switched fiber optic wired and/or wireless communication
systems and related methods to increase the range of wired and/or
wireless peer-to-peer communication systems. In one embodiment, the
optically-switched fiber optic wired and/or wireless communication
system may include a head-end unit (HEU) having an optical switch
bank. A plurality of fiber optic cables, each of the plurality of
fiber optic cables comprising at least one optical fiber, are
configured to carry a Radio-over-Fiber (RoF) signal from the HEU to
a plurality of remote access points. A first one of the plurality
of remote access points is configured to form a corresponding first
cellular coverage area where a first peer device is located. A
second one of the plurality of remote access points is configured
to form a corresponding second, different cellular coverage area
where a second peer device is located. The optical switch bank is
configured to dynamically establish a RoF-based optical link over
at least one of the plurality of fiber optic cables such that the
first peer device communicates with the second peer device at least
in part over the RoF-based optical link. These systems and methods
can overcome the limitations of traditional wired/wireless
peer-to-peer communications by combining the low loss, high
bandwidth nature of optical fiber with an appropriate optical
switching network to enhance coverage (where needed). In one
embodiment, the optically-switched fiber optic wired/wireless
communication system is a RoF-based link system. In another
embodiment, the RoF-based link system is nearly protocol
transparent (i.e., independent of protocol).
Before discussing specifics regarding exemplary embodiments of
optically-switched fiber optic wired/wireless communication systems
disclosed herein starting with FIG. 4, FIGS. 1-3 are first set
forth and discussed to describe a generalized embodiment of an
optical-fiber-based wireless picocellular system. In this regard,
FIG. 1 is a schematic diagram of a generalized embodiment of an
optical-fiber-based wireless picocellular system 10 (also referred
to herein as "system 10"). The system 10 includes a head-end unit
(HEU) 20, one or more transponder or remote antenna units 30, or
simply referred to herein as "remote units 30", and an optical
fiber radio frequency (RF) communication link 36 that optically
couples the HEU 20 to the remote unit 30. As discussed in detail
below, the system 10 has a picocell 40 substantially centered about
the remote unit 30. The remote units 30 form a picocellular
coverage area 44. The HEU 20 is adapted to perform or to facilitate
any one of a number of RF-over-fiber applications, such as radio
frequency identification (RFID), wireless local area network (WLAN)
communication, Bluetooth.RTM., or cellular phone service. Shown
within the picocell 40 is a device 45. The device 45 may be a
hand-held communication device (e.g., a cellular telephone or
personal digital assistant (PDA)), a personal computer, a video
monitor, or any other device that is capable of communicating with
a peer device. The device 45 may have an antenna 46 associated with
it.
Although the embodiments described herein include any type of
optically-switched fiber optic wired/wireless communication system,
including any type of RoF system, an exemplary RoF distributed
communication system 11 is provided in FIG. 2 to facilitate
discussion of the environment in which the peer-to-peer
communication between two devices in different cells is enabled.
FIG. 2 includes a partially schematic cut-away diagram of a
building infrastructure 12 that generally represents any type of
building in which the RoF distributed communication system 11 might
be employed and used. The building infrastructure 12 includes a
first (ground) floor 14, a second floor 16, and a third floor 18.
The floors 14, 16, 18 are serviced by the HEU 20, through a main
distribution frame 22, to provide a coverage area 24 in the
building infrastructure 12. Only the ceilings of the floors 14, 16,
18 are shown in FIG. 2 for simplicity of illustration.
In an example embodiment, the HEU 20 is located within the building
infrastructure 12, while in another example embodiment, the HEU 20
may be located outside of the building infrastructure 12 at a
remote location. A base transceiver station (BTS) 25, which may be
provided by a second party such as a cellular service provider, is
connected to the HEU 20, and can be co-located or located remotely
from the HEU 20. In a typical cellular system, for example, a
plurality of base transceiver stations are deployed at a plurality
of remote locations to provide wireless telephone coverage. Each
BTS serves a corresponding cell and when a mobile station enters
the cell, the BTS communicates with the mobile station. Each BTS
can include at least one radio transceiver for enabling
communication with one or more subscriber units operating within
the associated cell.
A main cable 26 enables multiple fiber optic cables 32 to be
distributed throughout the building infrastructure 12 to remote
units 30 to provide the coverage area 24 for the first, second and
third floors 14, 16, and 18. Each remote unit 30 in turn services
its own coverage area in the coverage area 24. The main cable 26
can include a riser cable 28 that carries all of the uplink and
downlink fiber optic cables 32 to and from the HEU 20. The main
cable 26 can also include one or more multi-cable (MC) connectors
adapted to connect select downlink and uplink optical fiber cables
to a number of fiber optic cables 32. In this embodiment, an
interconnect unit (ICU) 34 is provided for each floor 14, 16, 18,
the ICUs 34 including a passive fiber interconnection of optical
fiber cable ports. The fiber optic cables 32 can include matching
connectors. In an example embodiment, the riser cable 28 includes a
total of thirty-six (36) downlink and thirty-six (36) uplink
optical fibers, while each of the six (6) fiber optic cables 32
carries six (6) downlink and six (6) uplink optical fibers to
service six (6) remote units 30. Each fiber optic cable 32 is in
turn connected to a plurality of remote units 30 each having an
antenna that provides the overall coverage area 24.
In this example embodiment, the HEUs 20 provide electrical
radio-frequency (RF) service signals by passing (or conditioning
and then passing) such signals from one or more outside networks 21
to the coverage area 24. The HEUs 20 are electrically coupled to an
electrical-to-optical (E/O) converter 38 within the HEU 20 that
receives electrical RF service signals from the one or more outside
networks 21 and converts them to corresponding optical signals. The
optical signals are transported over the riser cables 28 to the
ICUs 34. The ICUs 34 include passive fiber interconnection of
optical fiber cable ports that pass the optical signals over the
fiber optic cables 32 to the remote units 30 to provide the
coverage area 24. In an example embodiment, the E/O converter 38
includes a laser suitable for delivering sufficient dynamic range
for the RoF applications, and optionally includes a laser
driver/amplifier electrically coupled to the laser. Examples of
suitable lasers for the E/O converter 38 include laser diodes,
distributed feedback (DFB) lasers, Fabry-Perot (FP) lasers, and
vertical cavity surface emitting lasers (VCSELs).
The HEUs 20 are adapted to perform or to facilitate any one of a
number of RoF applications, including but not limited to
radio-frequency identification devices (RFIDs), wireless local area
network (WLAN) communications, Bluetooth.RTM., and/or cellular
phone services. In a particular example embodiment, this includes
providing WLAN signal distribution as specified in the Institute of
Electrical and Electronics Engineers (IEEE) 802.11 standard, i.e.,
in the frequency range from 2.4 to 2.5 GigaHertz (GHz) and from 5.0
to 6.0 GHz. In another example embodiment, the HEUs 20 provide
electrical RF service signals by generating the signals directly.
In yet another example embodiment, the HEUs 20 coordinate the
delivery of the electrical RF service signals between client
devices within the coverage area 24.
The number of optical fibers and fiber optic cables 32 can be
varied to accommodate different applications, including the
addition of second, third, or more HEUs 20. In this example, the
RoF distributed communication system 11 incorporates multiple HEUs
20 to provide various types of wireless service to the coverage
area 24. The HEUs 20 can be configured in a master/slave
arrangement where one HEU 20 is the master and the other HEU 20 is
a slave. Also, one or more than two HEUs 20 may be provided
depending on desired configurations and the number of coverage area
24 cells desired.
FIG. 3 is a schematic diagram of an exemplary embodiment of the
optical fiber-based wireless picocellular system 10 of FIG. 1. In
this exemplary embodiment, the HEU 20 includes a service unit 50
that provides electrical RF service signals for a particular
wireless service or application. The service unit 50 provides
electrical RF service signals by passing (or conditioning and then
passing) such signals from one or more outside networks 223, as
described below. In a particular embodiment, this may include
providing ultra wide band-impulse response (UWB-IR) signal
distribution in the range of 3.1 to 10.6 GHz. Other signal
distribution is also possible, including WLAN signal distribution
as specified in the IEEE 802.11 standard, i.e., in the frequency
range from 2.4 to 2.5 GHz and from 5.0 to 6.0 GHz. In another
embodiment, the service unit 50 may provide electrical RF service
signals by generating the signals directly.
The service unit 50 is electrically coupled to an E/O converter 60
that receives an electrical RF service signal from the service unit
50 and converts it to corresponding optical signal, as discussed in
further detail below. In an exemplary embodiment, the E/O converter
60 includes a laser suitable for delivering sufficient dynamic
range for the RF-over-fiber applications, and optionally includes a
laser driver/amplifier electrically coupled to the laser. Examples
of suitable lasers for the E/O converter 60 include laser diodes,
distributed feedback (DFB) lasers, Fabry-Perot (FP) lasers, and
vertical cavity surface emitting lasers (VCSELs).
The HEU 20 also includes an O/E converter 62 electrically coupled
to the service unit 50. The O/E converter 62 receives an optical RF
service signal and converts it to a corresponding electrical
signal. In one embodiment, the O/E converter 62 is a photodetector,
or a photodetector electrically coupled to a linear amplifier. The
E/O converter 60 and the O/E converter 62 constitute a "converter
pair" 66.
In an exemplary embodiment, the service unit 50 includes an RF
signal modulator/demodulator unit 70 that generates an RF carrier
of a given frequency and then modulates RF signals onto the
carrier. The modulator/demodulator unit 70 also demodulates
received RF signals. The service unit 50 also includes a digital
signal processing unit ("digital signal processor") 72, a central
processing unit (CPU) 74 for processing data and otherwise
performing logic and computing operations, and a memory unit 76 for
storing data, such as system settings, status information, RFID tag
information, etc. In an exemplary embodiment, the different
frequencies associated with the different signal channels are
created by the modulator/demodulator unit 70 generating different
RF carrier frequencies based on instructions from the CPU 74. Also,
as described below, the common frequencies associated with a
particular combined picocell are created by the
modulator/demodulator unit 70 generating the same RF carrier
frequency.
With continuing reference to FIG. 3, in one embodiment, a remote
unit 30 includes a converter pair 66, wherein the E/O converter 60
and the O/E converter 62 therein are electrically coupled to an
antenna system 100 via an RF signal-directing element 106, such as
a circulator. The RF signal-directing element 106 serves to direct
the downlink and uplink electrical RF service signals, as discussed
below. In an exemplary embodiment, the antenna system 100 includes
a broadband (3.1 to 10.6 GHz) antenna integrated into a fiber optic
array cable.
The remote units 30 may be a typical access point device, or part
of a typical access point device. In one embodiment, the remote
units 30 may be typical WLAN access points. In another embodiment,
the remote units 30 may be typical broadband access points, or
ultra-wide broadband (UWB) access points. In yet another
embodiment, the remote units 30 may be co-existent (both WLAN and
broadband-UWB) access points. The remote units 30 may be any device
capable of forming a picocell or other cellular coverage area
substantially centered about the remote unit 30 in which devices
within the picocell or other cellular coverage area can communicate
with the remote unit 30. In a further embodiment, the remote units
30 differ from the typical access point device associated with
wireless communication systems in that the preferred embodiment of
the remote unit 30 has just a few signal-conditioning elements and
no digital information processing capability. Rather, the
information processing capability is located remotely in the HEU
20, and in a particular example, in the service unit 50. This
allows the remote unit 30 to be very compact and virtually
maintenance free. In addition, the preferred exemplary embodiment
of the remote unit 30 consumes very little power, is transparent to
RF signals, and does not require a local power source.
With reference again to FIG. 3, an exemplary embodiment of the
optical fiber RF communication link 136 includes a downlink optical
fiber 136D having a downlink optical fiber input end 138 and a
downlink optical fiber output end 140, and an uplink optical fiber
136U having an uplink optical fiber input end 142 and an uplink
optical fiber output end 144. The downlink and uplink optical
fibers 136D and 136U optically couple the converter pair 66 at the
HEU 20 to the converter pair 66 at the remote unit 30.
Specifically, the downlink optical fiber input end 138 is optically
coupled to the E/O converter 60 of the HEU 20, while the downlink
optical fiber output end 140 is optically coupled to the O/E
converter 62 at the remote unit 30. Similarly, the uplink optical
fiber input end 142 is optically coupled to the E/O converter 60 of
the remote unit 30, while the uplink optical fiber output end 144
is optically coupled to the O/E converter 62 at the HEU 20.
In one embodiment, the system 10 employs a known telecommunications
wavelength, such as 850 nanometers (nm), 1300 nm, or 1550 nm. In
another exemplary embodiment, the system 10 employs other less
common but suitable wavelengths such as 980 nm.
Exemplary embodiments of the system 10 include either single-mode
optical fiber or multi-mode optical fiber for the downlink and
uplink optical fibers 136D and 136U. The particular type of optical
fiber depends on the application of the system 10. For many
in-building deployment applications, maximum transmission distances
typically do not exceed 300 meters. The maximum length for the
intended RF-over-fiber transmission needs to be taken into account
when considering using multi-mode optical fibers for the downlink
and uplink optical fibers 136D and 136U. For example, it has been
shown that a 1400 MHz/km multi-mode fiber bandwidth-distance
product is sufficient for 5.2 GHz transmission up to 300 m.
In one embodiment, a 50 micrometers (.mu.m) multi-mode optical
fiber is used for the downlink and uplink optical fibers 136D and
136U, and the E/O converters 60 operate at 850 nm using
commercially available VCSELs specified for 10 Gigabits per second
(Gb/s) data transmission. In a more specific exemplary embodiment,
OM3 50 .mu.m multi-mode optical fiber is used for the downlink and
uplink optical fibers 136D and 136U.
The system 10 also includes a power supply 160 that generates an
electrical power signal 162. The power supply 160 is electrically
coupled to the HEU 20 for powering the power-consuming elements
therein. In one embodiment, an electrical power line 168 runs
through the HEU 20 and over to the remote unit 30 to power the E/O
converter 60 and the O/E converter 62 in the converter pair 66, the
optional RF signal-directing element 106 (unless the optional RF
signal-directing element 106 is a passive device such as a
circulator), and any other power-consuming elements (not shown). In
an exemplary embodiment, the electrical power line 168 includes two
wires 170 and 172 that carry a single voltage and that are
electrically coupled to a DC power converter 180 at the remote unit
30. The DC power converter 180 is electrically coupled to the E/O
converter 60 and the O/E converter 62 in the remote unit 30, and
changes the voltage or levels of the electrical power signal 162 to
the power level(s) required by the power-consuming components in
the remote unit 30. In one embodiment, the DC power converter 180
is either a DC/DC power converter or an AC/DC power converter,
depending on the type of electrical power signal 162 carried by the
electrical power line 168. In an exemplary embodiment, the
electrical power line 168 includes standard
electrical-power-carrying electrical wire(s), e.g., 18-26 AWG
(American Wire Gauge) used in standard telecommunications and other
applications. In another exemplary embodiment, the electrical power
line 168 (shown as a dashed line in FIG. 3) runs directly from the
power supply 160 to the remote unit 30 rather than from or through
the HEU 20. In another exemplary embodiment, the electrical power
line 168 includes more than two wires and carries multiple
voltages.
In another embodiment, the HEU 20 is operably coupled to the
outside networks 223 via a network link 224.
With reference to the optical-fiber-based wireless picocellular
system 10 of FIGS. 1 and 3, the service unit 50 generates an
electrical downlink RF service signal SD ("electrical signal SD")
corresponding to its particular application. In one embodiment,
this is accomplished by the digital signal processor 72 providing
the modulator/demodulator unit 70 with an electrical signal (not
shown) that is modulated onto an RF carrier to generate a desired
electrical signal SD. The electrical signal SD is received by the
E/O converter 60, which converts this electrical signal SD into a
corresponding optical downlink RF signal SD' ("optical signal SD'
"), which is then coupled into the downlink optical fiber 136D at
the input end 138. It is noted here that in one embodiment, the
optical signal SD' is tailored to have a given modulation index.
Further, in an exemplary embodiment, the modulation power of the
E/O converter 60 is controlled (e.g., by one or more gain-control
amplifiers, not shown) to vary the transmission power from the
antenna system 100. In an exemplary embodiment, the amount of power
provided to the antenna system 100 is varied to define the size of
the associated picocell 40, which in exemplary embodiments range
anywhere from about a meter across to about twenty meters
across.
The optical signal SD' travels over the downlink optical fiber 136D
to the output end 140, where it is received by the O/E converter 62
in the remote unit 30. The O/E converter 62 converts the optical
signal SD' back into an electrical signal SD, which then travels to
the RF signal-directing element 106. The RF signal-directing
element 106 then directs the electrical signal SD to the antenna
system 100. The electrical signal SD is fed to the antenna system
100, causing it to radiate a corresponding electromagnetic downlink
RF signal SD'' ("electromagnetic signal SD").
When the device 45 is located within the picocell 40, the
electromagnetic signal SD'' is received by the antenna 46. The
antenna 46 converts the electromagnetic signal SD'' into an
electrical signal SD in the device 45, and processes the electrical
signal SD. The device 45 can generate electrical uplink RF signals
SU, which are converted into electromagnetic uplink RF signals SU''
("electromagnetic signal SU''") by the antenna 46.
When the device 45 is located within the picocell 40, the
electromagnetic signal SU'' is detected by the antenna system 100
in the remote unit 30, which converts the electromagnetic signal
SU'' back into an electrical signal SU. The electrical signal SU is
directed by the RF signal-directing element 106 to the E/O
converter 60 in the remote unit 30, which converts this electrical
signal into a corresponding optical uplink RF signal SU' ("optical
signal SU'"), which is then coupled into the input end 142 of the
uplink optical fiber 136U. The optical signal SU' travels over the
uplink optical fiber 136U to the output end 144, where it is
received by the O/E converter 62 at the HEU 20. The O/E converter
62 converts the optical signal SU' back into an electrical signal
SU, which is then directed to the service unit 50. The service unit
50 receives and processes the electrical signal SU, which in one
embodiment includes one or more of the following: storing the
signal information; digitally processing or conditioning the
signals; sending the signals on to one or more outside networks 223
via network links 224; and sending the signals to one or more
devices 45 in the picocellular coverage area 44. In an exemplary
embodiment, the processing of the electrical signal SU includes
demodulating the electrical signal SU in the modulator/demodulator
unit 70, and then processing the demodulated signal in the digital
signal processor 72.
FIGS. 4-6 illustrate three embodiments of protocol-independent RoF
wireless presence. All of these embodiments have a WLAN-requesting
switching network to initiate a protocol-independent peer-to-peer
connection.
FIG. 4 is a schematic diagram of using an exemplary embodiment of
an optically-switched fiber optic wired/wireless communication
system to allow proprietary protocol data transfer between
peer-to-peer devices according to an exemplary embodiment. In FIG.
4, a peer device 202 is located in a different cellular coverage
area ("cell") than a peer device 204. The peer device 202 is
capable of communicating with an access point 208 through a
wireless connection (indicated by the dashed line) when the peer
device 202 is within a first cell defined by the access point 208.
The peer device 204 is capable of communicating with an access
point 210 through a wireless connection (indicated by the dashed
line) when the peer device 204 is within a second cell defined by
the access point 210. The access points 208 and 210 may be
broadband access points, or broadband transponders. In one
embodiment, the access points 208 and 210 may be similar to the
remote units 30 described above with respect to FIG. 3, where the
remote units 30 include a converter pair 66, wherein the E/O
converter 60 and the O/E converter 62 therein are electrically
coupled to an antenna system 100 via an RF signal-directing element
106, such as a circulator.
The access points 208 and 210 are optically coupled to a HEU 20 by
optical fibers in a fiber optic cable (as represented by the solid
lines between the access points 208 and 210 and the HEU 20). In one
embodiment, the optical fibers may connect the access points 208
and 210 to the HEU 20 in a manner similar to that illustrated in
FIGS. 2 and/or 3. FIG. 4 illustrates using a device 200 (e.g., PDA
or cellular telephone) that is different than the peer device 202
to request the peer-to-peer switching. The device 200 sends a
peer-to-peer request to a WLAN access point 206 (as indicated by
the dashed line). The WLAN access point 206 is also optically
coupled to the HEU 20 by optical fibers in a fiber optic cable (as
represented by the solid lines between the WLAN access point 206
and the HEU 20) such that the peer-to-peer request is sent from the
WLAN access point 206 to the HEU 20.
When the HEU 20 receives the peer-to-peer request, an optical
switch bank 212 dynamically selects the appropriate optical fibers
to connect the access points 208 and 210 so that the peer devices
202 and 204 associated with the access points 208 and 210 can
communicate with each other. Once the optical switch bank 212
dynamically selects the appropriate optical fibers to connect the
access points 208 and 210, the peer device 202 can communicate
wirelessly with the access point 208 using whatever protocol the
peer device 202 and the access point 208 are capable of using, and
the peer device 204 can communicate wirelessly with the access
point 210 using whatever protocol the peer device 204 and the
access point 210 are capable of using. In this manner, peer-to-peer
communication between the peer devices 202 and 204 in different
cells using different wireless protocols is enabled through the
optical switch bank 212 establishing a dynamic optical link between
the access points 208 and 210 of the two different cells.
This scenario could be used in medical applications such as a
hospital or other medical facility, where a doctor using a PDA
might request that high resolution images (X-ray, MRI, etc.) stored
on remote proprietary devices be displayed on a bedside
proprietary-protocol-based monitor. For example, the peer device
202 could have be a computer in a hospital records area that has
X-ray data stored on it. Through the use of the system shown in
FIG. 4, the data from the peer device 202 could be transmitted to
the peer device 204, which might be a computer terminal or other
monitor or display in a patient's room that is on a different floor
from the records room where the peer device 202 is located.
FIG. 5 is a schematic diagram of using an exemplary embodiment of
an optically-switched fiber optic wired/wireless communication
system to allow videoconferencing between peer-to-peer devices
according to an exemplary embodiment. In FIG. 5, a peer device 302
is located in a different cell than a peer device 304. The peer
device 302 is capable of communicating with an access point 308
through a wireless connection (indicated by the dashed line) when
the peer device 302 is within a first cell defined by the access
point 308. The peer device 304 is capable of communicating with an
access point 310 through a wireless connection (indicated by the
dashed line) when the peer device 304 is within a second cell
defined by the access point 310. The access points 308 and 310 may
be broadband access points, or broadband transponders. In one
embodiment, the access points 308 and 310 may be similar to the
remote units 30 described above with respect to FIG. 3, where the
remote units 30 include a converter pair 66, wherein the E/O
converter 60 and the O/E converter 62 therein are electrically
coupled to an antenna system 100 via an RF signal-directing element
106, such as a circulator.
The access points 308 and 310 are optically coupled to a HEU 20 by
optical fibers in a fiber optic cable (as represented by the solid
lines between the access points 308 and 310 and the HEU 20). In one
embodiment, the optical fibers may connect the access points 308
and 310 to the HEU 20 in a manner similar to that illustrated in
FIGS. 2 and/or 3. The exemplary system shown in FIG. 5 works in a
similar manner as that shown in FIG. 4. The scenario illustrated in
FIG. 5 differs from that of FIG. 4 in that one of the peer devices
302 or 304 initiates the connection, instead of requiring a
different device (e.g., PDA). This is applicable in situations
where the peer devices 302 and 304 both have WLAN access and a
broadband wireless (possibly proprietary-protocol) network and
desire to participate in a videoconference. Thus, in one
embodiment, the peer devices 302 and 304 may be computing devices,
such as laptop computers, the access points 308 and 310 may be
broadband access points, and the access points 306 and 314 may be
WLAN access points. For example, the embodiment of FIG. 5 could
utilize an existing low data rate WLAN that is insufficient for a
video application (e.g., 802.11b) by allowing a laptop computer to
place the request for a peer-to-peer connection on the low data
rate network, and have the video information transferred via a
peer-to-peer broadband higher data rate network based on
wireless/UWB USB. Thus, in FIG. 5, one of the peer devices 302 or
304 initiates a request for peer-to-peer communication. The peer
device 302 sends a communication request to the WLAN access point
306 or the peer device 304 sends a communication request to the
WLAN access point 314 (as indicated by the thin dashed lines). The
WLAN access points 306 and 314 are optically coupled to the HEU 20
by optical fibers in a fiber optic cable (as represented by the
solid lines between WLAN access point 306 and the HEU 20 and
between the WLAN access point 314 and the HEU 20) such that the
peer-to-peer request is sent from either the WLAN access point 306
or the WLAN access point 314 to the HEU 20.
When the HEU 20 receives the peer-to-peer request, an optical
switch bank 312 dynamically selects the appropriate optical fibers
to connect the access points 308 and 310 so that the peer devices
302 and 304 associated with the access points 308 and 310 can
communicate with each other. Once the optical switch bank 312
dynamically selects the appropriate optical fibers to connect the
access points 308 and 310, the peer device 302 can communicate
wirelessly with the access point 308 using whatever protocol the
peer device 302 and the access point 308 are capable of using, and
the peer device 304 can communicate wirelessly with the access
point 310 using whatever protocol the peer device 304 and the
access point 310 are capable of using. In this manner, peer-to-peer
communication between the peer devices 302 and 304 in different
cells using different wireless protocols is enabled through the
switch bank 312 establishing a dynamic optical link between the
access points 308 and 310 of the two different cells.
FIG. 6 is a schematic diagram of using an exemplary embodiment of
an optically-switched fiber optic wired/wireless communication
system to allow communication between peer-to-peer devices through
co-existent access points according to an exemplary embodiment. In
FIG. 6, a peer device 402 is located in a different cell than a
peer device 404. The peer device 402 is capable of communicating
with an access point 408 through a wireless connection (indicated
by the thin dashed line on the left) when the peer device 402 is
within a first cell defined by the access point 408. The peer
device 404 is capable of communicating with an access point 410
through a wireless connection (indicated by the thin dashed line on
the right) when the peer device 404 is within a second cell defined
by the access point 410. The access points 408 and 410 may be
coexistent access points. In one-embodiment, the access points 408
and 410 may have both WLAN and broadband (e.g. broadband-UWB)
capabilities. The access points 408 and 410 are optically coupled
to a HEU 20 by optical fibers in a fiber optic cable (as
represented by the solid lines between the access points 408 and
410 and the HEU 20). In the embodiment where access point 408 is a
coexistent access point, a filter 409 may be used to separate
broadband signals, such as 2.4 Megahertz signals, from WLAN
signals, such as 802.11 signals, that may be received over the
fiber optic cable from the coexistent access point 408. In the
embodiment where access point 410 is a coexistent access point, a
filter 411 may be used to separate broadband signals, such as 2.4
Megahertz signals, from WLAN signals, such as 802.11 signals, that
may be received over the fiber optic cable from the coexistent
access point 410. In one embodiment, the HEU 20 automatically
determines that communication between the peer devices 402 and 404
are possible based on the frequency of the signals received from
the peer devices 402 and 404. In one embodiment, the HEU 20 may
sense the radio frequency band content of the signals received from
the peer devices 402 and 404, with one peer device being located in
each cell. The HEU 20 may then automatically determine a switch
configuration by using the optical switch bank 412 to connect the
cells that have common radio frequency bands via a RoF-based
optical link. This automatic connection eliminates the need for a
peer-to-peer request from one of the peer devices 402 or 404, or
from a third device. In one embodiment, the optical fibers may
connect the access points 408 and 410 to the HEU 20 in a manner
similar to that illustrated in FIGS. 2 and/or 3. The exemplary
system shown in FIG. 6 works in a similar manner as that shown in
FIGS. 4 and 5. The scenario illustrated in FIG. 6 differs from that
of FIG. 5 in that only one network with coexistent capabilities is
used in place of two separate networks, and that the broadband
signals may be filtered from the WLAN signals. For example, the
videoconferencing application example mentioned with respect to
FIG. 5 would also be suitable in FIG. 6.
When the HEU 20 receives the peer-to-peer request from either peer
device 402 or 404 through the access point 408 or 410, a switch
bank 412 dynamically selects the appropriate optical fibers to
connect the access points 408 and 410 so that the peer devices 402
and 404 associated with the access points 408 and 410 can
communicate with each other. Once the switch bank 412 dynamically
selects the appropriate optical fibers to connect the access points
408 and 410, the peer device 402 can communicate wirelessly with
the access point 408 independent of protocol. In this manner,
peer-to-peer communication between the peer devices 402 and 404 in
different cells using different wireless protocols is enabled
through the switch bank 412 establishing a dynamic optical link
between the access points 408 and 410 of the two different
cells.
FIG. 7 is a schematic diagram of an exemplary embodiment of an
optical switching bank at a HEU of an optically-switched fiber
optic wired/wireless communication system. In FIG. 7, fiber optic
cables 702-1 through 702-n and 704-1 through 704-n optically couple
the HEU 20 to the access point(s) of N peer devices. For example,
the fiber optic cable 702-1 optically couples the HEU 20 to the
access point of Peer 1 and fiber optic cable 704-n optically
couples the HEU 20 to the access point of Peer N. In one
embodiment, each fiber optic cable 702-1 through 702-n and 704-1
through 704-n has a transmit optical fiber and a receive optical
fiber. For example, the fiber optic cable 702-1 has an optical
transmit fiber 702t and an optical receive fiber 702r, and the
fiber optic cable 704-n has an optical transmit fiber 704t and an
optical receive fiber 704r. Thus, FIG. 7 illustrates how when a
request for Peer 1 to communicate with Peer N is received at the
HEU 20, an optical switch bank 712 will dynamically link the two
cells where Peer 1 and Peer N are located by coupling the optical
transmit fiber 702t and the optical receive fiber 702r associated
with Peer 1 to the optical receive fiber 704r and the optical
transmit fiber 704t associated with Peer N. In one embodiment, the
HEU 20 may include optical amplifiers 706. In one embodiment, the
optical amplifiers 706 may be added when it is desired to be able
to enable communication between peer devices that are more than 300
meters apart.
FIG. 8 is a schematic diagram of an exemplary embodiment of using
optical amplification and splitting at a HEU of an
optically-switched fiber optic wired/wireless communication system
for broadcasting video to peer-to-peer devices. In FIG. 8, an
incoming fiber optic cable 802 couples a device that provides a
video source (not shown) to the HEU 20. The fiber optic cable 802
may include an optical transmit fiber 802t and an optical receive
fiber 802r in one embodiment. The HEU 20 of FIG. 8 includes a video
broadcasting unit 806 that splits the video coming in over the
optical transmit fiber 802t to multiple outgoing fiber optic cables
804-1 to 804-n, each of which may be optically coupled to a peer
device. Each fiber optic cable 804-1 through 804-n has a transmit
and a receive optical fiber. For example, the fiber optic cable
804-1 has an optical transmit fiber 804-1t and an optical receive
fiber 804-1r, and the fiber optic cable 804-n has an optical
transmit fiber 804-nt and an optical receive fiber 804nr. Thus,
FIG. 8 illustrates how a HEU 20 that is optically coupled to a
video source may broadcast video (e.g., high-definition (HD) TV
(HDTV), videoconferencing, etc.) over optical fibers to multiple
peer devices in different locations. In one embodiment, the video
broadcasting unit 806 may also provide amplification of the video
signal. Note that in certain embodiments of the video broadcasting
embodiment of FIG. 8, not all of the optical transmit and receive
fibers need be used. For example, the optical transmit fiber 802t
of the fiber optic cable 802, as well as the optical transmit
fibers 804-1t through 804-nt, are not necessarily used when a video
signal is broadcast using the embodiment of FIG. 8.
FIG. 9 is a schematic diagram of an exemplary embodiment of an
optically-switched fiber optic wired/wireless communication system
that illustrates an exemplary connection between a HEU and
broadband transponders in two different locations. In FIG. 9, the
HEU 20 is optically coupled to broadband transponders 906 and 914,
which may be in different cellular coverage areas. Each of the
broadband transponders 906 and 914 is optically coupled to the HEU
20 via a fiber optic cable 900, which has an electrical power line
902 and one or more optical fibers 904. The broadband transponder
906 has an RF input/output 908, which in one embodiment is an RF
antenna, a DC input/output 910, and an optical input/output 912.
The broadband transponder 914 has an RF input/output 916, which in
one embodiment is an RF antenna, a DC input/output 918, and an
optical input/output 920.
FIG. 10 is a schematic diagram of an exemplary embodiment of a
broadband transponder that may be used in an exemplary embodiment
of an optically-switched fiber optic wired/wireless communication
system. FIG. 10 shows one embodiment of the broadband transponder
914 from FIG. 9 with more internal details. The broadband
transponder 906 in FIG. 9 may be similar to the broadband
transponder 914. The fiber optic cable 900 having the electrical
power line 902 and optical fibers 904 optically couples the
broadband transponder 914 to the HEU 20 (as shown in FIG. 9). The
broadband transponder 914 may have an RF input/output 916In and
916Out, which in one embodiment is an RF antenna, a DC input/output
918, and an optical input/output 920In and 920Out. In one
embodiment, the broadband transponder 914 may also include a laser
diode 922, a photo detector 924, and a transimpedance amplifier
926. In one embodiment, optical switches 905 and 907 enable
selections between the RF input/output 916In and 916Out and the
optical input/output 920In and 920Out.
FIG. 11 is a schematic diagram of an exemplary embodiment of a HEU
of an optically-switched fiber optic wired/wireless communication
system. FIG. 11 illustrates the details of an exemplary HEU that
can enable communication between peer devices in N cellular
coverage areas. The HEU 20 shown in FIG. 11 could be used in the
exemplary embodiment of an optically-switched fiber optic
wired/wireless communication system shown in FIG. 5. The HEU 20 of
FIG. 11 includes a peer-to-peer request processor 1100 and optical
switch bank 1102. The peer-to-peer request processor 1100 handles
the requests for communication that are received from the peer
devices. Together, the peer-to-peer request processor 1100 and the
optical switch bank 1102 are able to provide the high bandwidth
peer-to-peer connection between peer devices in different cellular
coverage areas independent of protocol. The HEU 20 can receive or
transmit signals to external networks over optical fiber 1104. A
transmit optical fiber 1110 and a receive optical fiber 1112
optically couple the HEU 20 to a WLAN access point or transponder
for a first peer device in a first cellular coverage area. An E/O
converter unit 1106 and an O/E converter unit 1108 provide any
necessary E/O or O/E conversion. A receive optical fiber 1114 and a
transmit optical fiber 1116 optically couple the HEU 20 to the
broadband access point or transponder for the first peer device. A
receive optical fiber 1118 and a transmit optical fiber 1120
optically couple the HEU 20 to a broadband access point or
transponder for a second peer device in a second cellular coverage
area. A receive optical fiber 1126 and a transmit optical fiber
1128 optically couple the HEU 20 to a WLAN access point or
transponder for the second peer device. An O/E converter unit 1122
and an E/O converter unit 1124 provide any necessary E/O or O/E
conversion. It is to be understood that there may be additional
sets of optical fibers if there are more than two peer devices.
FIG. 12 is a schematic diagram of an exemplary embodiment of a
RoF-based wireless presence communication system. FIG. 12 shows one
embodiment of how the RoF-based wireless presence communication
system might be implemented. Each of a plurality of peer devices
1202, 1204, 1206, 1208, 1210, 1212, and 1214 is in a different
cellular coverage area. They may be in different rooms in a
building, or even on different floors in a building. In one
embodiment, each of a plurality of peer devices 1202, 1204, 1206,
1208, 1210, 1212, and 1214 is located such that it may be capable
of communicating wirelessly via both a broadband transponder and a
wireless transponder, such as a WLAN, WiMax, or cellular
transponder. For example, the peer device 1202 is located such that
it may be located in a cellular coverage area defined by a
broadband transponder 1202B and a wireless transponder 1202W such
that peer device 1202 may be capable of communicating wirelessly
via both the broadband transponder 1202B and the wireless
transponder 1202W. Each of the other peer devices 1204, 1206, 1208,
1210, 1212, and 1214 is also associated with a broadband
transponder and a WLAN transponder such that each of the other
1204, 1206, 1208, 1210, 1212, and 1214 may be capable of
communicating wirelessly via both a broadband transponder and a
wireless transponder. The solid lines indicate a typical RoF
wireless deployment and the dotted lines indicate the peer-to-peer
fiber connection through the nearly protocol-transparent RoF
technology by using the optically-switched fiber optic
wired/wireless communication system disclosed herein. The typical
RoF wireless deployment connects the various rooms or cells to
external networks over optical fiber 1200, whereas the
optically-switched fiber optic wired/wireless communication system
disclosed herein, as shown by the dotted lines, allows
room-to-room, or cell-to-cell, communication between devices in
different cellular coverage areas, or between devices in the same
cellular coverage area that use different communication
protocols.
Thus, by using an optically-switched RoF wired/wireless
communication system, the communication range of peer-to-peer
communication systems may be increased. By using an optical switch
bank in a HEU to set up a dynamic link between the transponders in
two different cells, the devices in the two different cells can
communicate with each other over the optical fibers through the
HEU. This system overcomes the limitations of traditional
wired/wireless peer-to-peer communications by combining the low
loss, high bandwidth nature of optical fiber with an appropriate
optical switching network to enhance coverage (where needed). By
taking advantage of the fiber cable architecture of the
optically-switched fiber optic wired/wireless communication system,
such as a RoF WLAN picocell system, the peer-to-peer communication
range is extended to be cell-to-cell. This means that devices in
any two cells can communicate in the peer-to-peer mode independent
of their physical distance, such that the peer-to-peer range
extends across entire indoor installation areas. In addition, the
optically-switched fiber optic wired/wireless communication system
disclosed herein uses optical cable links that are nearly
transparent to wireless protocols, thereby eliminating proprietary
protocol compliance requirements.
Further, as used herein, it is intended that the terms "fiber optic
cables" and/or "optical fibers" include all types of single mode
and multi-mode light waveguides, including one or more optical
fibers that may be upcoated, colored, buffered, ribbonized and/or
have other organizing or protective structure in a cable such as
one or more tubes, strength members, jackets or the like. Likewise,
other types of suitable optical fibers include bend-insensitive
optical fibers, or any other expedient of a medium for transmitting
light signals. An example of a bend-insensitive optical fiber is
ClearCurve.RTM. Multimode fiber commercially available from Corning
Incorporated.
Many modifications and other embodiments set forth herein will come
to mind to one skilled in the art to which the embodiments pertain
having the benefit of the teachings presented in the foregoing
descriptions and the associated drawings. Therefore, it is to be
understood that the description and claims are not to be limited to
the specific embodiments disclosed and that modifications and other
embodiments are intended to be included within the scope of the
appended claims. It is intended that the embodiments cover any
modifications and variations of the embodiments provided they come
within the scope of the appended claims and their equivalents.
Although specific terms are employed herein, they are used in a
generic and descriptive sense only and not for purposes of
limitation.
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